Every scientific journey begins with an idea. These ideas can go one of two ways: 1) after countless trials and brainstorms, they actually work; 2) after countless trials and brainstorms, they don’t. I think you can guess which one happens more often.
This summer, I've been working out in Newport, Oregon at the Hatfield Marine Science Center. Hatfield is operated by Oregon State University and hosts groups like the Cooperative Institute for Marine Resource Studies and the Marine Mammal Institute, as well as researchers and staff from Oregon Dept. of Fish & Wildlife, US Dept. of Fish & Wildlife, and NOAA. I'm here at Hatfield working on some of my dissertation research with the help of the ORCAA lab, Oregon State's animal bioacoustics group. I came to the ORCAA lab as a visiting graduate student about a month ago with intentions of testing out some ideas. Ideas that, when I posed them, were more like off-handed comments to my advisor rather than valid approaches to realistic data collection.
Since my blogs seem to be few and far between these days, let me back up a tiny bit. As I've mentioned before, I’m currently working on my PhD at Syracuse University with Dr. Susan Parks. My interests are in pinniped behavior and physiology, and for my dissertation, I’m looking at the variation in male harbor seal mating behavior and its influence on reproductive success. I’m also interested in the effects of shipping noise on harbor seals during the breeding season, but that’s another blog post for another time.
|Harbor seal (Phoca vitulina) (Photo: Ron Niebrugge)|
A few months ago, as I was furiously preparing for my PhD candidacy exam (one part proposal defense, one part general knowledge exam, all parts stressful), I met with Susan to discuss how I could get the data that I wanted for the project I was proposing. I wanted underwater movements of harbor seals during the breeding season. I wanted to map out male territories and really figure out how and where they were spending their time when they were below the surface. Harbor seals, along with the majority of phocids (i.e., true seals), mate underwater. Underwater behavior of any marine mammal is difficult to obtain. We, as researchers, are limited in our visual observations to what happens above water. The best method we have to tracking animals subsurface is tagging. But tagging is expensive, time consuming, and logistically difficult — it typically involves getting a boat and a team of able-bodied persons, capturing the animal, and gluing a tag to its fur. It’s doable, but not with solely my grad student resources. Susan and I began spitting out other ideas:
“What about how they track fish, like a tiny PIT tag?”
“Can we localize with a fish tag?”
“They do it for salmon, no?”
“But how could we get the tag on the seal?”
“Some sort of remote attachment, so you wouldn’t have to capture them.”
“Could we feed it to them?”
“That probably wouldn’t be a good idea…”
“I guess we could just shoot it at them in a paintball.”
And there you have it, ladies and gentleman. The mildly sarcastic comment that snowballed into a cross-country trip to Oregon and countless hours of researching glues and paintballs.
|Vemco V6 Acoustic Tags|
After a bit of post-meeting research, I came across some small high frequency acoustic transmitters (made by Vemco, pictured on the right) that are used to study fish movement. They’re small, only about 16mm in length, and they emit 180 kHz signals about every 30 seconds. These acoustic signals are picked up on receivers that are strategically moored in the study site. By looking at differences in the times of arrival of specific signals, it’s possible to determine the location of the transmitter, i.e. the tag, i.e. the animal of interest. Acoustic tags are great for looking at subsurface behavior because of how efficiently sound travels underwater (it’s much more efficient compared to air – you can read more about that here). These tags seemed perfect! They were small enough to fit in a paintball, they were the right kind of tag for studying underwater movement of individuals, and they emitted signals that were above the hearing threshold of harbor seals (and killer whales)*.
*Researchers have also used 69 kHz tags (instead of 180 kHz) to monitor fish populations. The problem with these tags is that seals and sea lions can hear at 69 kHz. Implanting a tag that emits a sound in the hearing range of the fish’s predator is basically attaching a dinner bell to the study organism. When considering using acoustic tags on the seals, I wanted to make sure that they (and their predators) couldn’t hear the acoustic signal being emitted. That way I could avoid any potential behavioral disturbance (or increased predation) caused by the sound coming from the tag.
I took my PhD candidacy exam, finished the semester, and packed my bags for Oregon, where ORCAA commander in chief Holger Klinck had agreed to help me test this weird tag attachment idea.
Current emotions: Excited.
Things we had to figure out:
- How do we get the tag inside the paintball?
- What kind of glue do we use? – something that doesn’t solidify inside the paintball, but cures almost immediately to the seal…hmmm does this product even exist?
- How do we close the paintball once the tag and the glue are inside?
- Will it actually stick to the seal? – we were going to need a real seal to test that one…
And thus began the Amazon binge-purchasing. I bought glues. Super glues. Rapid cure super glues. Super instant curing no drip super glues. Veterinary grade surgical glues. One-minute instant mix two-part epoxies. Clear-dry power grip instant grab all-purpose interior adhesives. I also bought some regular paintballs and some empty paintball shells. And thanks to my paintballing sister, I already had the gun.
Current emotions: Overwhelmed – who knew there were so many options for adhesives?
The next step was to get the tag into the shell and fill it with glue. This took a bit of finagling, but I finally did it! I was so proud! I made three types of paintball tags. The first were regular paintballs that I emptied, stuffed with a tag, and filled with super glue (the green ones in the picture below). I sealed them with some glue and a sprinkle of baking soda. It turns out that baking soda is an accelerant for cyanoacrylates (fancy name for super glue). A tiny bit of baking soda and BOOM that super glue is SOLID. The second type of tag ball was basically the same as the first, but I used the empty paintball shells. Bonus – no emptying of paint required (the clear ones in the picture below). I was most proud of the third kind. These were half filled with super glue and half filled with baking soda. In theory, when it hit the seal, the tag would cure instantly to the fur of the animal because of the addition of the accelerant.
Current emotions: Feelin’ creative and accomplished.
|So many paintballs with tags! So much super glue on my fingers!|
|So proud of my science!|
I’m going to keep this long post from becoming too long and just tell you that it didn’t work. No tags stuck to anything.
Current emotions: Disappointed :(
|Assembling the tiny crossbow|
But this is science! So what do we do? We brainstorm more ideas! And what do we do when those don’t work either?? We brainstorm even more ideas! I went from my failed paintballs, to thinking about crossbows, tiny pistol crossbows, compound and recurve bows, drones (no one would buy me drones though…). After lots of trial and error, with an emphasis on the error, I landed on the pistol crossbow. It was small, manageable, and didn’t have too much power. I crafted some bolts out of wooden dowels, foam floats, electrical tape, PVC end caps, fishing line, empty paintball shell halves (might as well use them if I’ve already got them, right?), and of course, duct tape. With a little finesse and the right adhesive, I shot these homemade arrows out of my little crossbow and somehow got a tag to stick to my target. I. was. shocked. Did all of my brainstorming actually just pay off??
Current emotions: Chest-pounding, can-crushing, fire-breathing, unstoppable POWER.
|Fancy homemade crossbow arrows and a successful tag attachment!|
At this point it had been a roller coaster of successes and failures, which I thought was going to end with my, what could only be described as, legendary tagging success. However, after some preliminary field-testing, it was revealed that in order to make these tags work in the locations I wanted them to work, I would have to outfit the study area with an impractical number of receivers. Had all the time and research and effort and crossbow target practice all been for naught? Probably.
Current emotions: Uggggghhhhh seriously?? COME ON. I just got the tags to stick!
Back to the drawing board. Conversations with Holger, conversations with Susan, and conversations with Holger and Susan at the same time led us all to the conclusion that the classic tagging approach would probably be the most logical way to go about getting my data. Luckily, it’s looking like I’ll be able to collaborate with some other groups here in Newport on a tagging trip that’s already planned for next year. My sample size will be lower, it’s not exactly the data that I thought I was going to get, it’s not even in the same field site I thought I’d be working, but thus is life. As a scientist, you can’t be married to a certain data collection method or even to a certain location. You have to keep the big picture in mind – what were the original scientific questions/objectives? If you’re still able to get at these major objectives, then you’re probably still doing alright. Any data I can get to better understand the underwater mating behavior of these seals is beneficial for conservation and even just marine mammal biological knowledge in general. There’s still so much we don’t know about the organisms that live in our oceans (even ones like seals that spend part of their lives on land), but slowly and surely, we’re picking away at the mysteries.
Current emotions: Back to being excited. This scientific journey, though so far has been more madness then brilliance, is only just beginning. New pinniped adventures await!
FUN SCIENCE FACT #36: Sea otters (Enhydra lutris) have the densest fur of any mammal -- up to 1 MILLION hairs per square inch! This thick fur is essential for thermoregulating/keeping warm in cold water. It works by trapping a layer of air near the body of the animal. Air is much easier to heat than water, and when this air is kept warm, the otter is kept warm. Lots of animals use this method for thermoregulation, not just otters! (Think of a bird when it ruffles up its feathers and gets all puffy). Because of the importance of their fur to survival, oil spills are a major concern for sea otters. Crude oil can penetrate the fur, ruining the air layer and its insulating properties. A decrease in core body temperature can cause long-term organ damage, vascular system failure, and even death. Wow this fun science fact took a morbid turn. Sorry about that...
Here's a cute picture of some sea otters. And you can read more about sea otters here.
|Photo: Michael Baird|